From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [RFC PATCH V2 3/3] Ixgbevf: Add migration support for ixgbevf driver Date: Wed, 25 Nov 2015 14:28:05 +0200 Message-ID: <20151125142437-mutt-send-email-mst@redhat.com> References: <1448372298-28386-1-git-send-email-tianyu.lan@intel.com> <1448372298-28386-4-git-send-email-tianyu.lan@intel.com> <20151124230551-mutt-send-email-mst@redhat.com> <56554994.1090305@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org, alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, b.reynal-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org, bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, carolyn.wyborny-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, donald.c.skidmore-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, eddie.dong-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, nrupal.jani-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, agraf-l3A5Bk7waGM@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org, emil.s.tantilov-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, gerlitz.or-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, mark.d.rustad-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, eric.auger-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, intel-wired-lan-qjLDD68F18P21nG7glBr7A@public.gmane.org, jeffrey.t.kirsher-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, jesse.brandeburg-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, john.ronciak-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, matthew.vick-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, mitch.a.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, shannon.nelson-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, weiyang-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, zajec5-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org To: Lan Tianyu Return-path: Content-Disposition: inline In-Reply-To: <56554994.1090305-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Wed, Nov 25, 2015 at 01:39:32PM +0800, Lan Tianyu wrote: > On 2015=E5=B9=B411=E6=9C=8825=E6=97=A5 05:20, Michael S. Tsirkin wrot= e: > > I have to say, I was much more interested in the idea > > of tracking dirty memory. I have some thoughts about > > that one - did you give up on it then? >=20 > No, our finial target is to keep VF active before doing > migration and tracking dirty memory is essential. But this > seems not easy to do that in short term for upstream. As > starters, stop VF before migration. =46rankly, I don't really see what this short term hack buys us, and if it goes in, we'll have to maintain it forever. Also, assuming you just want to do ifdown/ifup for some reason, it's easy enough to do using a guest agent, in a completely generic way. > After deep thinking, the way of stopping VF still needs tracking > DMA-accessed dirty memory to make sure the received data buffer > before stopping VF migrated. It's easier to do that via dummy writing > data buffer when receive packet. >=20 >=20 > --=20 > Best regards > Tianyu Lan